1. Field of the Invention
The present invention relates to a method, system, and computer program product for updating class assignments for data sets during a recall operation.
2. Description of the Related Art
A policy based storage management framework specifies how data having certain characteristics is associated with different pools of storage space that will store such data, as well as how the data will be managed throughout its lifecycle. A policy based storage management framework provides constructs including data classes, storage classes, and management classes that are used to select storage devices and settings for a data set based on the characteristics of the data set. A data class specifies data set logical attributes, such as data file type, record length, logical data storage space requirements, expiration and retention dates for the data, etc. A storage class defines a set of storage services, such as random access specifications, sequential access specifications, guaranteed space, performance criteria, etc. A management class specifies availability and retention management requirements for data, such as hierarchical storage management (HSM), expiration, backup frequency, retention of backup copies, etc.
An automatic class selection (ACS) routine receives a request to create or access a data set and then selects and assigns data, storage, and management classes that apply to the data set based on characteristics of the data set, e.g., application that generated data set, data set name, date, owner of data set and/or application, etc. The final selection is of a storage group based on the data, storage, and management classes assigned to the data set. The storage group provides the allocation of physical storage space for the data sets Data sets can be members of one data class, but be assigned to different storage and/or management classes, which determine to which storage group the data file is assigned.
Over time, system demands may change, and the appropriate data, storage, and management classes for a data set may have changed as attributes of the data set have changed, such as available space, I/O activity directed to the data set, free space errors, etc. For instance, when the ACS routine was written, an application may have been able to use the data set successfully with a standard data set size of four gigabytes. Over time the same application is required to save more then four gigabytes of data causing the data set allocation to fail due to the data set system limitation. At this point the customer has to take action to alter the assigned data class so that the extended addressability attribute is specified. This extended addressability attribute is a feature that allows a data set to exceed its original data set system limitation. However, in most cases it is difficult for customers to identify how to rectify system limitations and performance problems caused by increased system work load. Further, the customer may have a new release of the operating system and storage manager with new features that could benefit the customer's environment however the feature is never implemented.